In his finely wrought portrait “Maestro: Leonard Bernstein,’’ Hershey Felder taps into the ineradicable sadness his Lawrence-born, Harvard-educated subject grappled with as he considered his own unfulfilled expectations.

It wasn’t that Bernstein developed a Brando-like contempt for his craft and spent decades phoning it in, but rather that, like Mailer — another man of multifarious talents, appetites, and ambitions who got swept up in the passions of his times — he allowed himself to be pulled in too many directions.

So there’s a tang of irony to the title of Felder’s solo show, now at the Paramount Center Mainstage in a production presented by ArtsEmerson. As he considers what it all added up to, the Bernstein of “Maestro’’ bitterly regrets that he did not devote more of his life to composing, his true love, and thus did not leave behind the masterwork of which he was capable.

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Written and performed by Felder, “Maestro’’ is clearly designed for a general audience; for those steeped in classical music it may feel like Bernstein 101. But Felder does not sand away the edges of a complicated man, and he largely avoids the twin perils that threaten any bioplay: an “And then I wrote’’ format and a mawkish tone. When a matinee crowd responded, “Aww,’’ to Bernstein’s childhood memory of his stern father at last buying him a piano, Felder quelled the gush of sentiment by sardonically echoing the audience. Then he moved on with his story.

Though framed as a monologue woven through Bernstein’s final concert program in 1990, just months before his death, “Maestro’’ takes place on a stage that contains not just a grand piano but also artifacts from an old-fashioned TV studio — a tripod-mounted camera, towering klieg lights — apparently to suggest the mediagenic dimensions of Bernstein’s career as public personality. (In reality, Bernstein conducted his final concert at Tanglewood, in August 1990.)

Felder, who wrote “Maestro,’’ gives short shrift to a key aspect of Bernstein’s public persona: his fervently liberal politics. Bernstein makes a passing reference to “talking politics from the stage and getting laughed off like the village idiot,’’ and briefly revisits the fund-raiser for the Black Panthers that he and his wife, Felicia, held in their New York apartment — an episode that inspired Tom Wolfe’s withering “Radical Chic.’’ (Bernstein alludes angrily to “a lousy two-bit journalist’’ who used Felicia “to get at me.’’)

Bernstein was devoted to his family. He also had gay affairs. It is when he describes his guilt over leaving Felicia for a man that “Maestro’’ delves deepest into sentiment.

As Felder moves through Bernstein’s life and career, the performer captures Bernstein’s restless energy, his combination of self-confidence and vulnerability, and his flair for drama (and melodrama, as when Bernstein breathlessly compares Aaron Copland to Moses). Felder does not attempt mimicry, though, and there’s no way to replicate Lenny’s magnificent visage or the electric charge of his conducting style. The audience gets a taste of that at an emotionally climactic juncture in “Maestro,’’ as Felder plays Wagner’s “Liebestod’’ while Bernstein leads an orchestra through the piece on a video screen that resembles a large, tattered manuscript.

Felder introduces the notion of Bernstein occupying a musical “continuum’’ early in “Maestro,’’ and the influence exerted on him by other musical titans, such as Boston Symphony Orchestra music director Serge Koussevitsky (“the father I never had’’) is a constant theme. In describing the impact on him of the death of George Gershwin — whom Felder will soon portray on the same stage in his show “George Gershwin Alone’’ — Bernstein says: “It’s the only thing I ever really wanted — to be the next great American Composer.’’

By most yardsticks, if not his own, Bernstein’s achievements were staggering. The score for “West Side Story’’ alone would be enough for most composers, not to mention “Candide,’’ “On the Town,’’ and “Wonderful Town.’’ As music director of the New York Philharmonic and guest conductor with countless other orchestras, he became a household name. He used his populist touch to extend the reach of classical music with his televised “Young People’s Concerts.”

But he was sneered at by atonal composers, even though he helped bring their work to a wider audience, and remained ambivalent about his own success. In one of the most powerful scenes in “Maestro,’’ in a tone of self-mockery that verges on self-loathing, Bernstein challenges the audience to sing a snatch of one of his sonatas, song cycles, or operas.

“No one gives a God-damn about conductors,’’ Bernstein declares. “The only ones they care about are composers. All of them have serious pieces. . . . At least one serious work that every single one of you know, that each of you can sing, that each of you bows down to as if they’re gods!’’ He then intones the opening “ta-da-da-da’’ from Beethoven’s Fifth Symphony.

“Maestro’’ is bracketed by Felder’s performance of excerpts from “Somewhere,’’ from “West Side Story,’’ with Bernstein’s haunting melody floating beneath Stephen Sondheim’s eternally heartbreaking yet hopeful lines: “There’s a place for us/ Somewhere a place for us. . .’’

What makes “Maestro’’ poignant is Felder’s persuasive demonstration that Bernstein could never quite be sure the same was true for him.